876,
You seemed to have missed what they're saying. Noone will argue that it's not a movie. However, they will argue against it just being a movie.

That's like saying, "It's a chair, It's just a Chair!"
They're saying, "Yes, it's a chair, but it's a green chair with Red Dots, I hadn't ever thought about chairs like that."
or
"That chair is a rocking chair. That makes me sad because it makes me think of my Grandmother."

It's the emotional and thought provoking responce that makes the difference. Obviously the movie didn't mean mutch to you and you didn't get much out of it. Fine. You have a right to your opinion, but don't criticise people for not interpreting it the way you did. (Note: I'm not criticising you for interpreting it in a different way, but that you berate people for finding more or a different meaning than you did.)

This is your life. Make of it what you will.